CreateMinimap.as

private function CreateMinimap():void
{
	// create a buffer the same size as your game world
	// fill it with nothing (0% alpha and no pixels drawn on it)
	minimapDisplay = new BitmapData(WORLD_WIDTH, WORLD_HEIGHT, true, 0x00000000);
	
	// loop over the game world exploration grid
	var gh:Number = Global.exploredMap.rows;
	var gw:Number = Global.exploredMap.columns;
	
	for (var gy:Number = 0; gy < gh; gy++)
	{
		for (var gx:Number = 0; gx < gw; gx++)
		{
			// if the tile has been explored, draw it on the minimapDisplay
			if (Global.exploredMap.getCell(gx, gy))
			{
				// draw a cyan 100% alpha pixel to show that we have explored this tile
				minimapDisplay.setPixel32(gx, gy, 0xFF00FFFF);
			}
		}
	}
}

override-render.as

override public function render():void
{
	// draw everything else
	super.render();
	
	// draw minimapDisplay centered
	FP.buffer.copyPixels(
		minimapDisplay, 
		minimapDisplay.rect, 
		new Point(
			int((FP.width - minimapDisplay.width) * 0.5),
			int((FP.height - minimapDisplay.height) * 0.5));
}